The first documented interaction between a long‐tailed weasel (Mustela frenata) and a plains spotted skunk (Spilogale interrupta) carcass

Abstract A novel interaction between a long‐tailed weasel (Mustela frenata) and a plains spotted skunk (Spilogale interrupta) carcass is detailed. In November 2020, a farmer in Edmunds County in north‐central South Dakota sent in a video recording of a long‐tailed weasel with a spotted skunk carcass. Location of the event, carcass condition, and recorded behavior of the long‐tailed weasel offer probable, but unconfirmed, evidence that the spotted skunk was killed by the long‐tailed weasel.

. The United States Fish and Wildlife Service is currently conducting a review of the conservation status of the plains spotted skunk in response to concerns over perceived population declines (Federal Register, 2012).
Research on spotted skunks has been limited, possibly because some consider them a nuisance species (Crabb, 1948;Kinlaw, 1995;Knight, 1994;Powell et al., 2017). Only 71 studies across Spilogale spp. were published from 1990 to 2019, of which 16 focused on plains spotted skunks. Information on spotted skunks in the Great Plains region is limited to a species description (Crabb, 1948), two species status evaluations (Choate et al., 1974;Tyler & Lodes, 1980), a report on incidental captures in South Dakota (Fino et al., 2019), and a description of weasel (Mustela spp.) and plains spotted skunk den use (Polder, 1968). Acknowledging the need for more information on the ecology of eastern and plains spotted skunks, researchers have begun addressing the knowledge gap by publishing >20 studies on eastern and plains spotted skunk in 2020 and 2021, but no new studies have occurred in the northern Great Plains.
Mephitids use various antipredator defense strategies when interacting with sympatric mammalian carnivores or birds of prey.
The long-tailed weasel (M. frenata) is one of the smallest members of the family Mustelidae (~170-280 g; Elsasser & Parker, 2008), whereas the plains spotted skunk is one of the smallest members of the family Mephitidae (~400-670 g; Fino et al., 2019, Higdon & Gompper, 2020. The long-tailed weasel is a bold (Armitage, 1961) generalist predator that typically hunts small-to-medium-sized prey (Sheffield & Thomas, 1997) but is capable of diet switching as relative prey abundances change (Proulx, 2019). Long-tailed weasels employ many hunting strategies, actively hunting in search of prey in underground burrows, on the ground, and arboreally (Vaughan, 1961). Their most common diet items include small rodents, lagomorphs, and game birds (Polderboer et al., 1941), but long-tailed weasels have been documented predating least (M. nivalis) and short-tailed (M. erminea) weasels (Gamble, 1981), and big brown bats (Eptesicus fuscus; Mumford, 1969). Interspecific interactions have not been documented between plains spotted skunks and long-tailed weasels, though in Iowa, both species commonly used Franklin's ground squirrel (Poliocitellus franklinii) and pocket gopher (Geomys bursarius) excavations as primary dens in areas with tall grass, which could instigate such interactions (Polder, 1968). Polder (1968) (Figure 1), placed it on top of a small piece of farming machinery, backed away to allow the weasel to return and retrieve the carcass, and recorded the interaction using his cellular phone camera. In December 2020, the farmer provided images and a 64-s video of the interaction, which is described herein. Initially, the weasel approached and repeatedly circled the farm machinery where the spotted skunk was placed. The weasel eventually climbed to the carcass, bit it, dropped to the ground with the carcass in its mouth, and retreated with the carcass to nearby hay bales. The images and video were used to confirm the carcass as a spotted skunk and the predator as a long-tailed weasel. The video is embedded (Video 1) and archived (https://openp rairie.sdsta te.edu/nrm_stude ntwor k/1/). The interaction may indicate the weasel killed the skunk or was scavenging skunk carrion. Long-tailed weasels may scavenge (DeVault et al., 2011;Elbroch et al., 2017), but there is no evidence of weasels scavenging a mephitid carcass. However, the location of the encounter and condition of the carcass suggests that the spotted skunk was likely killed by the weasel. The interaction occurred in a rural county (i.e., 1.4 people and 0.66 housing units/ km 2 ; United States Census Bureau, 2020) that was almost entirely farmland (~99.9%; USDA, 2017). The site where the interaction occurred received little human traffic and no paved roads were within 18 km, reducing the potential that the weasel scavenged a roadkill. Furthermore, no physical signs of injury associated with a vehicle collision were observed, and the carcass did not have signs of rigor mortis, indicating the spotted skunk was recently deceased . It is possible, though not confirmed, that spotted skunk mortality could result from ingesting rodenticides near home and farm buildings, but the nearest farm building was substantially further from the interaction site (~1.3 km) than the reported maximum winter travel distance (465 m; DeVan, 1982) or expected movement rates for long-tailed weasels based on home range sizes in agricultural landscapes (Gehring & Swihart, 2004). It is also unlikely that the long-tailed weasel usurped prey from another predator given that they are among the smallest predators in the carnivore guild, and predators of spotted skunks are capable of killing weasels; therefore, any attempt to scavenge from a shared predator would risk injury or death of the weasel (Palomares & Caro, 1999). Finally, the carcass was not partially consumed, as would be expected if it had been scavenged following predation by another species. Consequently, the evidence suggests that the recorded interaction was the result of a predatory killing of a spotted skunk by a long-tailed weasel.

CO N FLI C T O F I NTE R E S T
The authors declare that there is no conflict of interest. F I G U R E 1 Plains spotted skunk carcass that was dropped by a long-tailed weasel (left) after disturbance by humans and the long-tailed weasel retrieving the carcass (right) after it was placed on farm equipment by observers on 12 November 2020 in South Dakota (images courtesy of Sean Christiansen of Edmunds County, South Dakota, used with permission).

V I D E O 1
The first documented interaction between a longtailed weasel (Mustela frenata) and a plains spotted skunk carcass (Spilogale interrupta).

DATA AVA I L A B I L I T Y S TAT E M E N T
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.